Agriculturally active ingredients (agrochemicals) are often provided in the form of concentrates suitable for dilution with water. Many forms of agricultural concentrates are known and these consist of the active ingredient and a carrier, which can include various components. Water-based concentrates are obtained by dissolving, emulsifying and/or suspending agriculturally active materials in water. Due to the relatively complex supply chain for crop protection agents, such concentrate formulations can be stored for long periods and may be subjected during storage and shipping to extreme temperature variations, high-shear and repetitive vibration patterns. Such supply chain conditions can increase the likelihood of formulation failure such as, for example, flocculation, thickening and sedimentation.
In some cases it may be desirable to combine different agrochemicals in a single formulation taking advantage of the additive properties of each separate agrochemical and optionally an adjuvant or combination of adjuvants that provide optimum biological performance. For example, transportation and storage costs can be minimized by using a formulation in which the concentration of the active agrochemical(s) is as high as is practicable and in which any desired adjuvants are “built-in” to the formulation as opposed to being separately tank-mixed. The higher the concentration of the active agrochemical(s) however, the greater is the probability that the stability of the formulation may be compromised, or that one or more components may phase separate. In addition formulation failure can be more challenging to avoid when multiple active ingredients are present because of physical or chemical incompatibilities between these chemicals such as, for example, when one active ingredient is an acid, a base, an oily liquid, a hydrophobic crystalline solid or a hydrophilic crystalline solid and the other active ingredient(s) has or have different properties.
It also may be desirable to improve the effectiveness of the agrochemicals by controlling the release rate of agrochemical into the application site from the formulation. In particular it may be desirable to combine agrochemicals in a single formulation and control their release rates independently, for instance in cases where the modes of action of the agrochemicals renders them antagonistic if both are delivered at the same rate.
In addition, spray tank mixes can contain a variety of chemicals and adjuvants that may interact and change the effectiveness of one or more of the agrochemicals included therein. Incompatibility, poor water quality and insufficient tank agitation can lead to reduced effectiveness of sprays, phytotoxicity and can affect equipment performance.
Pesticide-comprising aqueous polymer dispersions with a mean particle size of the dispersed particles of <1000 nm which are obtained from miniemulsion polymerization of ethylenically unsaturated monomers are known, for example, from US 2008/0171658. A limitation of polymer dispersions of this type is that the miniemulsions are stabilized by conventional surfactants and therefore have small particle size and high specific surface area, which can result in a rapid release of the agrochemical(s) contained therein.
Considering the variety of conditions and special situations under which agrochemical liquid concentrate formulation are stored, shipped and used around the world, there remains a need for aqueous polymer dispersions comprising agrochemicals, including water-soluble, water-dispersible or water-sensitive agrochemicals, having a mean particle size of the dispersed particles of >1000 nm and which provide additional stability benefits under at least some of those conditions and situations. There is a further need for such formulations having high loading that are stable when diluted with water under a wide range of field conditions. There is yet a further need for such formulations that have controlled release rates of agrochemicals into the application site from the formulation and that work in complex aqueous systems and under a variety of conditions.
Similar properties are required in formulations in non-agricultural fields, for instance for controlled delivery of pharmaceutically active ingredients, for controlled delivery of flavors from foods, for controlled delivery of dyes or pigments, for controlled release of fragrances from cosmetic or household products, or for controlled delivery of enzymes and detergents in cleaning products. In these industries and others there is a need for the ability to prepare stable formulations of components that can be released to the target site upon application.